I also found the same thing on my 83sd, rear window leaking, removed the window and I just about freaked out but my auto body guy said,"relax" and as Pete Burton said" It is more doable than you think". The auto body guy took an air powerd wizzer and proceeded to cut out all the cancer. He left high spots where ever he could so the glass would sit right. Then he formed 2 pieces of L stock together and bent to fit. He then fit it so it becme the pinch weld where the glass sits, he drilled sm holes in the base of the L and pop rivetedon to the body, he then put some sort of smoo or body gooo, and reassembled it and installed the glass. That was almost 2 years ago and no leaks. steve 83sd